1. Field of the Invention
The present invention relates to a submerged nozzle mounting/dismounting apparatus for mounting a submerged nozzle on and dismounting the same from a molten metal vessel, such as a ladle or a tundish, in a continuous metal casting system.
2. Description of the Prior Art
The continuous metal casting system has a molten metal vessel such as a ladle or tundish. The molten metal vessel is provided with a slide valve device on and below the bottom wall of the vessel. The slide valve device comprises a bottom plate and a slide plate that is slidable relative to the bottom plate. The bottom plate and the slide plate have holes, respectively, through which molten metal in the molten metal vessel is caused to flow down. By suitably adjusting the position of the slide plate relative to the bottom plate, the degree of overlap of the holes of the two plates changes so that the flowrate of the molten metal flowing down the holes can be adjusted.
A submerged nozzle extends downward and is supported by a submerged nozzle holding mechanism provided below the slide valve device. The molten metal flowing down through the slide valve device is caused to flow into and through the submerged nozzle. The submerged nozzle is removably mounted to the slide valve. The submerged nozzle must be mounted to the slide valve when assembling the continuous casting system, while the submerged nozzle must be dismounted from the slide valve when the submerged nozzle is impaired.
Since the submerged nozzle is formed of bricks and is heavy, the entirely manual work for mounting and dismounting the submerged nozzle is hard and troublesome, and is undesirable in view of working conditions, because the submerged nozzle mounting and dismounting work needs to be carried out in the hot environment around the side valve device and requires heavy physical labor.
When replacing an eroded submerged nozzle with a new one using a mechanical mounting/dismounting means, the molten metal vessel loaded on a car is conveyed to a workshop, and the car mounted with the molten metal vessel is stopped at a predetermined position. Then, the eroded submerged nozzle is dismounted from the slide valve device, and then a new submerged nozzle is mounted on the slide valve device. However, in most cases, the position on the slide valve device at which the submerged nozzle is attached to the slide valve device does not coincide with the position of the submerged nozzle on the mechanical mounting/dismounting means and, consequently, the final positional adjustment of the mechanical mounting/dismounting means relative to the mounting position on the slide valve device must be carried out visually when mounting the submerged nozzle on or dismounting the same from the slide valve device. The operators must carry out this positional adjustment of the mechanical mounting/dismounting means unavoidably in a hot environment around the molten metal vessel.